Violent fire-driven convection can manifest as towering pyrocumulus (pyroCu) or pyrocumulonimbus (pyroCb) clouds, which can have devastating impacts on the environment and society. Their associated fire spread is erratic, unpredictable and not generally suppressible. Research into large pyroconvective events has mainly focused on the atmospheric processes involved in normal atmospheric convection, or on surface fire weather and associated fuel conditions. There has been comparatively less attention paid to the role of the fire itself in these coupled fire–atmosphere events. This paper draws on recent insights into dynamic fire propagation and extreme wildfire development to investigate how the fire influences the occurrence of violent pyroconvective events. A static heat source of variable dimension and intensity is used. This is accompanied by a companion paper that extends the analysis by including the effect of fire geometry on the pyroconvective plume. The analyses indicate that the spatial expanse and intensity of large fires are critical factors driving the development of pyroconvective plumes and can override the influence of the stability of the atmosphere. These findings provide motivation for further investigation into the effect of the fire’s attributes on the immediate atmosphere and have the potential to improve forecasting of blow-up fire events.

猛烈的火源对流可能表现为高耸的焦积云（pyroCu）或焦积云（pyroCb）云，这可能对环境和社会造成毁灭性影响。它们相关的火势蔓延是不稳定的，不可预测的并且通常不能被抑制。对大型热对流事件的研究主要集中在正常大气对流所涉及的大气过程，或地表着火天气和相关的燃料条件上。在这些耦合的火-气事件中，对火本身的作用的关注相对较少。本文利用对动态火势蔓延和极端野火发展的最新见解来研究火势如何影响剧烈的热对流事件的发生。使用尺寸和强度可变的静态热源。随附伴随文件，该文件通过包括火几何形状对热对流羽流的影响来扩展分析。分析表明，大火的空间扩展性和强度是驱动热对流羽流发展的关键因素，可以忽略大气稳定性的影响。这些发现为进一步研究火灾属性对邻近大气的影响提供了动力，并有可能改善爆炸性火灾事件的预测。分析表明，大火的空间扩展性和强度是驱动热对流羽流发展的关键因素，可以忽略大气稳定性的影响。这些发现为进一步研究火灾属性对邻近大气的影响提供了动力，并有可能改善爆炸性火灾事件的预测。分析表明，大火的空间扩展性和强度是驱动热对流羽流发展的关键因素，可以忽略大气稳定性的影响。这些发现为进一步研究火灾属性对邻近大气的影响提供了动力，并有可能改善爆炸性火灾事件的预测。